The Veterans Affairs Departmentís top health official abruptly resigned Friday amid the exploding scandal over delays in veteransí care.

VA Undersecrertary for Health Dr. Robert Petzel was already scheduled to retire later this summer, but VA Secretary Eric Shinseki asked for his resignation early.

In a statement, Shinseki thanked Petzel for his four decades of service at the department but said a change is needed.

ďAs we know from the veteran community, most veterans are satisfied with the quality of their VA health care, but we must do more to improve timely access to that care,Ē Shinseki said. ďI am committed to strengthening veteransí trust and confidence in their VA healthcare system.

VA officials would not say if any specific event triggered Petzelís forced resignation. On Thursday, he and Shinseki testified before the Senate Veteransí Affairs Committee about the recent care delay scandals.

On several occasions, when senators confronted the pair about past memos and studies about problems with veteransí health care access or appointment wait times, Shinseki claimed only limited knowledge of the reports. But Petzel said he had reviewed nearly all of them, and ordered corrections and further investigations.

VAís top leaders have been under fire in recent weeks since whistlebowers alleged that Phoenix VA Health Care officials doctored medical appointment wait times in an effort to hide problems in the health care system. They also have charged that the resulting care delays may have contributed to the deaths of 40 veteran patients.

Since then, similar care delay issues have surfaced in seven other cities.

On Thursday, officials from the VA Inspector Generalís office said they have found no definitive links so far between care delays and patient deaths, but have found serious issues with how quickly veterans can get medical appointments.

Officials from the American Legion earlier this month called for the resignations of Shinseki, Petzel, and Undersecretary for Benefits Allison Hickey in response to what they called a pattern of mismanagement throughout the department.

Shinseki told lawmakers that the Veterans Health Administration already has put in place numerous efforts to address appointment scheduling and wait time issues. But he also acknowledged that further improvement is needed.

Petzel had served as VAís top health official since February 2010. Dr. Robert Jesse, principal deputy undersecretary for health, will take over Petzelís role until a new permanent replacement is confirmed.

Earlier this month, Dr. Jeffrey Murawsky, director of VAís Great Lakes Health Care System, was nominated by the White House to replace Petzel.